The present invention relates to an oxidizing gas sensor having a gas sensing layer formed of a metal oxide semiconductor material on an insulating substrate so as to make resistance changes in concentration variations in oxidizing gas. The present invention also relates to an oxidizing gas production method.
There are known various metal oxide semiconductor gas sensors, each of which includes a sensor element that features a gas sensing layer formed of a metal oxide semiconductor material on an insulating substrate to detect concentration variations in oxidizing gas such as nitrogen oxide (NOx) in response to resistance changes in the gas sensing layer due to the transfer of electrons in a surface portion of the gas sensing layer.
In one type of metal oxide semiconductor gas sensor, the sensor element has a catalyst portion in contact with the gas sensing layer, as disclosed in International Publication WO 2004/048957A1, for improvement in gas detection performance.